Analysis of the storage capacity and charging and discharging power in energy storage systems based on historical data on the day-ahead energy market in Poland

The use of energy storage technology can contribute, among other things, to reducing emissions of pollutants and CO₂, as well as reducing electricity costs. Storage technologies can bring benefits especially in the case of a large share of renewable energy sources in the energy system, with high production variability. The article focuses on the analysis of storage system parameters, in particular, based on prices on the energy market in Poland. The relations between the charging and discharging system power as well as storage times guaranteeing profit were determined. The analyzes were carried out for historical data of the day-ahead market covering the years 2017–2019. Also, the analyzes included determining the required operational storage capacities for energy. Based on the described methodology, the required storage capacities were determined for the case of a system built of hydrogen generators, underground gas storage and fuel cells generating energy from hydrogen. Changes in the energy market in the analyzed period resulted in different results of analyzes for individual years and allowed for a broader assessment of the methodology used for the analysis.